The present invention relates to the making of molds for continuous casting machines, which molds are to be made of copper or copper alloys; more particularly, the present invention relates to the making of a mold, using a tubular copper or copper alloy blank, which tubular blank is shaped by means of a mandrel, as well as by means of forces acting on the tubular blank from the outside, which mandrel has the final dimensions and/or complementary contour of the internal contour of the mold to be made; the mandrel, of course, is to be removed following the forming and shaping process.
A method of the kind to which the inventions pertains and which is approved upon presently, is basically known through German Pat. No. 1,809,633 (see also U.S. Pat. No. 3,646,799). In accordance with this prior publication, an originally straight tube is forced, for example, onto a mandrel, which is curved, and has also the dimensions of the mold to be made. The tubular blank is just a little larger than the mandrel following forcing the tube onto the mandrel; together they are passed through a die by means of which the tube is now drawn onto the mandrel. Basically, this method is very valuable and many molds at the requisite accuracy and surface quality have been made in this fashion, particularly molds for continuous casting of steel have been made in this manner. The molds, particularly on account of the drawing process, have indeed sufficient hardness.
However, it was found that this mold making procedure when considered just by itself is quite expensive, and the manufacture is rather cumbersome and requires extensive machinery and trained personnel. Moreover, for improving the economy of existing casting machines, one has to an increasing extent larger molds.
Another factor having to do with the economy is that the down time of a machine is to be reduced. This means, molds should have a long use life and not require frequent exchange because during mold changing the machine itself is idle. This, of course, means that the use life of a mold has to be increased, and for this, in turn, it is necessary, to increase inter alia the hardness of the mold material. Also, the true-to-shape conditions are to be improved. On the other hand, it is apparent that an increase in hardness, particularly of a copper based mold material to be continued, with increased accuracy as to shape, means that the shaping forces generally for such a mold will have to be increased.